1. Field of the Invention
This invention relates in general to seals and more specifically to insulation sealing devices for inspection holes.
Safety precautions and legal duties often require periodic inspection of insulated process equipment (i.e. tanks, tank cars, pipelines, etc.) for evaluation of wall thickness or deterioration due to corrosion/or erosion. Non-destructive testing (NDT), such as ultrasonics, are periodically made for such determinations. Holes are cut through the insulation to facilitate the inspection and are quickly closed after test completion. The tests are periodically repeated to maintain progressive status at the designated location. Principally, the seals should be weatherproof, easily installed, and reusable.
2. Prior Art Higuera, U.S. Pat. No. 3,658,096 provided a spring-secured insulation plug. This patent was modified in Elesta, U.S. Pat. No. 3,827,462. Greenawalt, U.S. Pat. No. 4,091,842 then substituted a swage-securing arrangement.
These insulation seal invention have insuffiencies in various degrees in (1) involving complex spring and swage arrangements to secure the seals, (2) requiring special installation tools, such as for swaging, (3) allowing primary exposure of elastomeric material subject to deterioration by sand-blasting and other external wear, (4) requiring adhesives or caulking, and (5) involving limited weather sealing ability, particularly with corrugated insulation jackets.